Transmission assembly

ABSTRACT

The transmission assembly, specially for motor vehicles, has a housing, a drive shaft, a countershaft and an arrangement for changing the reduction ratio between the drive shaft and the countershaft which contains a continuously variable transmission and downstream thereof a mechanical transmission with shifting elements in the form of clutches and brakes and a planetary gear set for shifting the reverse gear and one or more forward gears.

FIELD OF THE INVENTION

The invention relates to a transmission assembly comprising a housing, adrive shaft, a countershaft and an arrangement for changing thereduction ratio between the drive shaft and the countershaft, whicharrangement has a continuously variable transmission and downstreamthereof a mechanical transmission with shifting elements in the form ofclutches and brakes, and a planetary gear set for shifting the reversegear and one or more forward gears.

BACKGROUND OF THE INVENTION

Continuously variable transmission (CVT) are variously known in the formof belt drive transmission or in the form of toroidal drives. TheApplicant's DE 198 44 374.9 thus describes a belt drive transmissionwhich has a first cone pulley pair upon a drive shaft and a second conepulley pair upon an output shaft, each cone pulley pair consisting of afirst pulley stationary in axial direction and a second cone pulleymovable in axial direction (respectively primary pulleys and secondarypulley). Between the cone pulley pairs extends a belt drive organ suchas a pushing linked band. The primary and secondary pulleys are adjustedby a pressure medium with the aid of an electronic control device whichvia electromagnetic actuators and hydraulic valves controls the pressurelevel of the adjusting spaces of primary pulley and secondary pulley.

The toroidal drive has been described, for example, in the Applicant'sWO 99/05433. It has input and output pulleys arranged in pairs andsituated coaxially to a common shaft with their inner faces toroidallyconfigured, the same as friction wheels placed between the pairs ofinput and output pulleys. The friction wheels are in frictional contactboth with the input pulleys and with the output pulleys and transmit byfrictional-engagement contact the torque transmitted to them by theinput pulley to the output pulley, the rotational speed of the frictionwheels being higher the greater the distance between their point ofcontact with the input pulley and the axis of rotation. The rotationalspeed of the output pulley, on the other hand, is higher the closer thecontact point between friction wheel and output pulley is to the axis ofrotation. By tilting the friction wheel sit is accordingly possiblecontinuously and arbitrarily to adjust the rotational speed of theoutput pulley. To this end, the axes of rotation of the friction wheelsare supported on a carrier which can be controlled via a swivelingdevice. Both input pulleys of both transmission assemblies are herenon-turnably connected with a torque shaft while both output pulleys ofboth transmission assemblies, which are disposed in the transmissionwith reciprocal mirror symmetry and side by side, are arranged upon acommon bushing turnably supported upon the torque shaft. The torqueshaft is penetrated by an input shaft which is connected with a startingelement of a motor vehicle such as a torque converter or a wet-runningstarting clutch of the prime mover of the vehicle.

The problem on which this invention is based is to reduce theinstallation space needed for this transmission assembly and to simplifythe oil supplies.

SUMMARY OF THE INVENTION

In the embodiment of the inventive transmission assembly, the parts ofthe mechanical transmission are disposed in a manner such thatdownstream of the continuously variable transmission is a brake for thereverse gear with integrated oil supply, that downstream of said brakeis a clutch for the second range, that downsream of said clutch is aplanetary gear set, that downstream of said planetary gear set is aclutch or the first range with integrated oil supply and that a spurpinion is downstream of said clutch.

This particular arrangement of the individual parts makes possible notonly a compact design with reduced need of space but also asimplification of the oil supplies which are integrated one in a brakeand one in a clutch. Besides, a modular construction of the transmissionassembly is possible, that is, in the final assembly only twofront-mounted units have to be mounted whereby the final assembly isaccelerated.

In the embodiment of the inventive transmission assembly, thearrangement of the parts of the mechanical transmission is selected sothat the clutch for the first range is interchanged with the spur pinionwhereby a shorter countershaft can be used and the spur pinion can besituated closer to the engine of the motor vehicle. Thereby the space inthe rear, that is, the part on the output side, is further reduced.

In the embodiment of the inventive transmission assembly, the parts ofthe mechanical transmission are disposed so that the clutch for thefirst range is interchanged with the spur pinion and the planetary gearset in the serial arrangement, which makes possible an alternative tyingof the planetary gear set and the output takes place via the webthereof; the countershaft can also be designed shorter here whereby theinstallation space in the rear part, that is, the part on the outputside of the transmission assembly, is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with referenceto the accompanying drawings in which:

FIG. 1 diagrammatically shows an axial section through a firstembodiment of the construction of the mechanical transmission;

FIG. 2 shows the transmission diagram of said first embodiment;

FIG. 3 shows the transmission diagram of the second embodiment; and

FIG. 4 shows the transmission diagram of the third embodiment accordingto the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the longitudinal section shown in FIG. 1 through the rear, that is,the output side range, of an inventive transmission assembly which isdownstream of the continuously variable transmission (not shown), thatis, either a belt drive of a toroidal drive the arrangement of theindividual parts is selected as follows.

Downstream of the brake 1 for the reverse gear with integrated oilsupply is a clutch 2 for the second range; downstream of said clutch 2is a planetary gear set 3; downstream of said planetary gear set 3 is aclutch 4 for the first range likewise with integrated oil supply;downstream of said clutch 4 is a spur pinion 5 which is in operativeconnection with the countershaft 6.

The arrangement of the individual parts of the mechanical transmissionmakes possible not only a compact design with simplified oil suppliesbut also a modular construction so that in the final assembly only twofront-mounted units have to be joined to accelerate the final assembly.

In FIG. 2 is shown the appertaining transmission diagram for theconstruction of the mechanical transmission explained in FIG. 1.

In another embodiment of the arrangement of the parts of the mechanicaltransmission, as it is to be understood from the transmission diagram ofFIG. 3, the parts are disposed so that the clutch 4 for the first rangeis exchanged with the spur pinion 5 whereby a shorter countershaft 6 canbe used and the spur pinion 5 moves closer to the continuously variabletransmission and thus to the engine of the motor vehicle. This means areduced installation space in the rear part of the transmissionassembly, that is, in the mechanical transmission.

In one other inventive embodiment shown in the transmission diagram inFIG. 4, the parts are arranged in the mechanical transmission so thatclutch 4 for the first range is exchanged with the spur pinion 5 and theplanetary gear set 6 whereby an alternative tying of the planetary gearset 3 is made possible by the output taking place via the web. Thecountershaft 6 can thereby be further shortened and thus theinstallation space of the rear part of the transmission assembly, thatis, in the mechanical transmission, can still be more reduced.

REFERENCE NUMERALS

-   1 brake-   2 clutch-   3 planetary gear set-   4 clutch-   5 spur pinion-   6 countershaft

1. A transmission assembly, especially for motor vehicles, comprising: a housing, a drive shaft, a countershaft; and an arrangement for changing the reduction ratio between the drive shaft and the countershaft which has a continuously variable transmission and drivingly downstream thereof a mechanical transmission with shifting elements in the form of clutches and brakes, and a planetary gear set for shifting of the reverse gear and one or more forward gear ranges; wherein the parts of the mechanical transmission are sequentially disposed as follows: beginning downstream of the continuously variable transmission is a brake (1) for the reverse gear with integrated oil supply; downstream and adjacent the brake (1) is a first clutch (2) for a second range; downstream and adjacent the first clutch (2) is a planetary gear set (3); downstream and adjacent the planetary gear set (3) is a second clutch (4) for a first gear range with an integrated oil supply; and downstream and adjacent the second clutch (4) is a spur pinion.
 2. A transmission assembly, especially for motor vehicles, comprising: a housing, a drive shaft, a countershaft; and an arrangement for changing the reduction ratio between the drive shaft and the countershaft which has a continuously variable transmission and downstream thereof a mechanical transmission with shifting elements in the form of clutches and brakes, and a planetary gear set for shifting of the reverse gear and one or more forward gear ranges; wherein the parts of the mechanical transmission are disposed as follows: downstream of the continuously variable transmission is a brake (1) for the reverse gear with an integrated oil supply; downstream of the brake (1) is a clutch (2) for a second gear rang; downstream of the clutch (2) is a planetary gear set (3); downstream of the planetary gear set (3) is a spur pinion (5); and downstream of the spur pinion (5) is a clutch (4) for a first range with integrated oil supply.
 3. A transmission assembly, especially for motor vehicles, comprising: a housing, a drive shaft, a countershaft: and an arrangement for changing the reduction ratio between the drive shaft and the countershaft which has a continuously variable transmission and downstream thereof a mechanical transmission with shifting elements in the form of clutches and brakes, and a planetary gear set for shifting the reverse gear and one or more forward gear ranges; wherein the parts of the mechanical transmission are disposed as follows: downstream of the continuously variable transmission is a brake (1) for the reverse gear with integrated oil supply; downstream of the brake (1) is a clutch (2) for a second gear range; downstream of the clutch (2) is a spur pinion (5); downstream of the spur pinion (5) is a planetary gear set (3); and downstream of the planetary gear set (3) is a clutch (4) for a first gear range with integrated oil supply.
 4. Transmission assembly, especially for motor vehicles, comprising a housing, a drive shaft, a countershaft and an arrangement for changing the reduction ratio between the drive shaft and the countershaft which has a continuously variable transmission and downstream thereof a mechanical transmission with shifting elements in the form at clutches and brakes, and a planetary gear set for shifting of the reverse gear and one or more forward gears, wherein the parts of the mechanical transmission are arranged sequentially along an axis of the drive shaft as follows: beginning downstream of the continuously variable transmission s a brake (1) for the reverse gear with integrated oil supply; downstream and adjacent the brake (1) is a first clutch (2) for the second range; downstream and adjacent the first clutch (2) is a planetary gear set (3); downstream and adjacent the planetary gear set (3) is a second clutch (4) for the first range with integrated oil supply; and downstream and adjacent the second clutch (4) is a spur pinion.
 5. Transmission assembly, specially for motor vehicles, comprising a housing, a drive shaft, a countershaft and an arrangement for changing the reduction ratio between the drive shaft and the countershaft which has a continuously variable transmission and downstream thereof a mechanical transmission with shifting elements in the form of clutches and brakes, and a planetary gear set for shifting of the reverse gear and one or more forward gears, wherein the parts of the mechanical transmission are sequentially disposed in a direction of power flow as follows: downstream of the continuously variable transmission is a brake (1) for the reverse gear with integrated oil supply; downstream of the brake (1) is a clutch (2) for the second range; downstream of the clutch (2) is a planetary gear set (3); downstream of the planetary gear set (3) is a spur pinion (5); and downstream of the spur pinion (5) is a clutch (4) for the first range with integrated oil supply.
 6. Transmission assembly, specially for motor vehicles, comprising a housing, a drive shaft, a countershaft end an arrangement for changing the reduction ratio between the drive shaft and the countershaft which has a continuously variable transmission and downstream thereof a mechanical transmission with shifting elements in the form of clutches and brakes, and a planetary gear set for shifting the reverse gear and one or more forward gears, wherein the parts of the mechanical transmission are sequentially disposed in a direction of power flow as follows: downstream of the continuously variable transmission is a brake (1) for the reverse gear with integrated oil supply; downstream of the brake (1) is a clutch (2) for the second range; downstream of the clutch (2) is a spur pinion (5): downstream of the spur pinion (5) is a planetary gear set (3); and downstream of the planetary gear set (3) is a clutch (4) for the first range with integrated oil supply. 